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A239362 Decimal expansion of Sum_{k>=1} 1/((3k-2)*(3k-1)*(3k)). 2
1, 7, 8, 7, 9, 6, 7, 6, 8, 8, 9, 1, 5, 2, 7, 0, 3, 9, 7, 9, 9, 7, 0, 8, 2, 5, 5, 1, 7, 9, 9, 0, 7, 5, 0, 6, 9, 0, 9, 1, 4, 3, 9, 2, 2, 5, 6, 7, 4, 9, 7, 7, 8, 0, 9, 5, 8, 7, 9, 7, 6, 5, 0, 4, 3, 7, 6, 5, 7, 2, 2, 1, 9, 7, 6, 9, 3, 6, 2, 2, 9, 2, 0, 2, 6, 2, 7 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

L. B. W. Jolley, Summation of series, Dover Publications Inc. (New York), 1961, p. 46 (series n. 250).

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..10000

FORMULA

Equals ( Pi*sqrt(3)/3 - log(3) )/4.

EXAMPLE

0.1787967688915270397997082551799075069091439225674977809587976504...

1/(1*2*3) + 1/(4*5*6) + 1/(7*8*9) + 1/(10*11*12) + 1/(13*14*15) + ...

MAPLE

evalf[100]((Pi*sqrt(3) - 3*log(3))/12 ); # G. C. Greubel, Aug 11 2019

MATHEMATICA

RealDigits[(Pi Sqrt[3]/3 - Log[3])/4, 10, 100][[1]]

PROG

(PARI) default(realprecision, 100); (Pi*sqrt(3) - 3*log(3))/12 \\ G. C. Greubel, Aug 11 2019

(MAGMA) SetDefaultRealField(RealField(100)); R:= RealField(); (Pi(R)*Sqrt(3) - 3*Log(3))/12; // G. C. Greubel, Aug 11 2019

(Sage) numerical_approx((pi*sqrt(3) - 3*log(3))/12, digits=100) # G. C. Greubel, Aug 11 2019

CROSSREFS

Cf. A164833: Sum_{k>=1} 1/((4k-2)*(4k-1)*(4k)).

Sequence in context: A010728 A291509 A153856 * A094819 A019861 A065470

Adjacent sequences:  A239359 A239360 A239361 * A239363 A239364 A239365

KEYWORD

nonn,cons

AUTHOR

Bruno Berselli, Mar 17 2014

STATUS

approved

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Last modified October 16 12:22 EDT 2021. Contains 348041 sequences. (Running on oeis4.)